CI: .travis.yml: rm ALL_TESTS, since it does not work for nix-build

and also just plainly does not passes itself, so it is useless in CI build setup

M  .travis.yml

.travis.yml

@@ -34,8 +34,6 @@ env:
     # - rev=nixos-unstable
     # - NIX_PATH="nixpkgs=https://github.com/nixos/nixpkgs/archive/$rev.tar.gz"
     - project='hnix'
-    # Enable all our tests in Cabal
-    - ALL_TESTS='yes'
     - allowInconsistentDependencies='false'
     - doJailbreak='false'
     - doCheck='true'